<ctype.h>: fix a stray `inline` that breaks C89 compatibility.

Bug: https://github.com/android/ndk/issues/2081
Change-Id: I8d63fb003510837c28dad0da9b0c6703a3487f7b
diff --git a/libc/include/ctype.h b/libc/include/ctype.h
index cb926a4..dc3f673 100644
--- a/libc/include/ctype.h
+++ b/libc/include/ctype.h
@@ -95,7 +95,7 @@
 
 /** Internal implementation detail. Do not use. */
 __attribute__((__no_sanitize__("unsigned-integer-overflow")))
-static inline int __bionic_ctype_in_range(unsigned __lo, int __ch, unsigned __hi) {
+__BIONIC_CTYPE_INLINE int __bionic_ctype_in_range(unsigned __lo, int __ch, unsigned __hi) {
   return (__BIONIC_CAST(static_cast, unsigned, __ch) - __lo) < (__hi - __lo + 1);
 }